Railroad hopper cars are commonly used to economically transport commodities between distantly spaced geographic locations. Such hopper cars include a hopper typically having a plurality of longitudinally spaced chutes. At the bottom of the car, each chute terminates in a chute opening. Hopper cars typically include a mounting flange provided about each standard opening on the bottom of the hopper car. Such hopper car mounting flanges typically define a series of apertures or openings arranged in a generally standard bolting pattern.
Dry granular commodities can be rapidly discharged from the hopper car through gate assemblies mounted in material receiving relation relative to the chute openings on the bottom of the hopper car. A frame of each gate assembly defines a discharge opening having a generally rectangular shape and through which such commodities are gravitationally discharged from the hopper car. A gate or door is slidably movable on the frame and a drive mechanism is provided for moving the gate between closed and open positions. In a closed position, the gate prevents discharge of the commodity from the hopper car. When the gate is opened, the commodity is gravitationally discharged through the discharge opening defined by the gate assembly. As will be appreciated by those skilled in the art, the commodity carried by the railroad hopper car places a significant columnar load on an upper surface of the gate and on the frame of the gate assembly. Any openings, recesses or grooves in any of the interconnected frame members of the gate assembly can significantly weaken or adversely affect both the strength and rigidity required of the frame of the gate assembly.
In effect, the gate assembly frame includes an upper portion disposed above an upper surface of the gate and a lower portion disposed below a lower surface of the gate. The upper portion of the gate assembly frame includes, toward an upper end thereof, a mounting flange designed to facilitate securement of the gate assembly to the hopper car. The upper portion of the gate assembly defines a first or upper discharge opening which approximates the size of the chute opening on the railcar. The lower portion of the gate assembly frame defines a second or lower discharge opening. Moreover, the lower portion of a typically gate assembly includes outwardly extending flange structure arranged in surrounding relation with the second or lower discharge opening.
Once a hopper car reaches an unloading site, the gate on the gate assembly is opened and gravity causes the commodity within the walled enclosure or hopper on the car to freely drop from the railcar's hopper through the discharge opening and into a take-away device. There are several common options for the take-away device. One option involves an open-pit having conveyance equipment, i.e., a belt-conveyor or pneumatic conveyor arranged toward a bottom thereof.
A second option involves a sealed pit using unloading “boots.” With this device, a boot is raised from beneath and between the rails and seals against the outwardly extending flange structure or “boot flange” on the bottom of the gate assembly. During discharge, the commodity falls from the hopper, passing into the boot, from whence the commodity is directed toward and deposited onto conveyance equipment under the rails. These unloading boots are available in several standard sizes. Typically, there is “standard” spacing between such unloading boots. Problematically, however, the spacings between the opening of the outlet gates is not always the same as the spacing between such unloading boots. Accordingly, the discharge openings on the gate assembly may not always vertically align with the discharge boot rising from beneath and between the rails and vice-versa. As such, commodity being discharge from the hopper car sometimes spills outside of the misaligned unloading boot and is lost. Such economical loss is simply unacceptable.
Another common option for directing a discharged commodity from the hopper car involves use of a portable unloading sled having a selectively operable conveyor. Unlike unloading pits, which are more or less permanently located, portable unloading sleds allow unloading of the railcar at almost any location where the railcar can be safely parked and accessed. These portable unloading sleds are specifically designed to fit between the top or upper surface of the rails and the bottom of the discharge gate assembly. To reduce the commodity lost during discharge and transfer of the commodity, the portable sleds abut with or against the “boot flange” on the bottom of the gate assembly.
Prior to the discharge of commodity from the railcar, the portable unloading sled is wheeled or otherwise moved into place on top of the rails and under the discharge outlet of the gate assembly. The conveyor is engaged or otherwise “turned ON” and the gate of the gate assembly is thereafter opened. The unloading sled serves to convey the commodity received from the hopper of the railcar into silos, truck-trailers, or is simply deposited onto the ground.
It is desirable for railroad hopper cars used in services which unload into a portable unloading sled to, at some time during their service life, have the capability of being moved or returned to service wherein the gate assembly is required to unload into an unloading boot. The rectangular boot flange opening, however, on one very common and/or popular gate assembly measures about 26.5 inches by about 56 inches. The rectangular boot flange opening on another very common and/or popular gate assembly measures about 25.25 inches by about 59 inches. As such, and when the most common and popular gate assemblies unload into a standard unloading boot, having an outside dimension of about 19 inches by about 48 inches, commodity being discharged from the hopper car often times spills outside of the unloading boot and is lost. Again, such an economical loss is simply unacceptable.
The Association of American Railroads (the “AAR”) has revised the Standard governing locking systems for gate assemblies used on hopper-type railroad cars. The revised Standard (S-233-2011) requires the locking/unlocking or latching/unlatching functions for the gate assembly to be integrated into the discharge gate operating mechanism. As such, rotation of a capstan in a direction to open the gate must first unlock or unlatch the gate and then move the gate from the closed position to the open position.
Thus, there is a continuing need and desire for a railcar discharge gate assembly which is readily adaptable to either unloading over an open pit or into an unloading boot while minimizing loss of commodity whereby significantly adding to the versatility of usage of the railcar while also satisfying the latest AAR Standard.